Flotation of sulphide ores



Patented Aug. 13, 1946 FLOTATION OF SULPHIDE ORES Cornelius H. Keller, San- Francisco, Calif., as-

signorto The Dow Chemical Company, Midland, Mich., a corporation of Michigan N Drawing. Application October 1-7, 1944,- Serial No. 559,117

11 Claims. (Cl. 209-166) This invention relates to the concentration of ores, minerals and the like by flotation, and has for its broad object the provision of certain improvements in the process.

In the froth flotation of ores, an ore pulp is first prepared by wet grinding to a suitable size with or without a suitable pH modifier. A suitable frothing agent and a flotation agent are then added. Upon agitating and aerating the mixture, the metalliferous values in the ore collect as a froth which can be readily overflowed or skimmed 01f and the metal values therein recovered.

Flotation agents, as, a broad class, are well known. Generally within the broad class subclassification is possible into several groups, each of which will difier from another in its flotation elfect. The present invention is concernedwith a group of agents which are not only good collectors, but are also highly selective in their action, enabling sulphide copper minerals, sulphide zinc minerals and others to be floated selectively from sulphide iron minerals. The new agents are obtainedas the reaction product of a carbocyclic acid halide, a monohydric aliphatic alcohol and an alkali thiocyanate', the chemical constitution of which is not fully known. These possess numerous advantages. For example, they are soluble to a useful extent in various organic solvents, such as am'yl alcohol and cresylic acid, thereby enabling the agent to be fed as a liquid. Further, these agents can be incorporated and utilized with other agents such as xanthates. When treated with an alkali hydroxide, these agents are converted into water soluble salts which can be fed as Water solutions.

The materials of the present invention are conveniently prepared by the interaction of any carbocyclic acid halide such as benz'oyl chloride, benzoyl bromide, furoyl chloride, furoyl bromide, or other carbocyclic acid'halide upon an alcoholic solution or suspensionof an alkali thiocyanate such as potassium thiocyanate, ammonium thiccyanate, sodium thiocyanate. Any aliphatic monohydric alcohol can be used and I have successfully employed ethyl, isopropyl, secondary butyl, N-amyl, N-butyl, octyl anda mixture of amyl alcohols (sold, under the trade-name Pentasol) and diethylcarbinol.

A typical example of the preparation of these materials follows: V8 mol. weight of a suitable alkali thiocyanate was triturated in a mortar with mol. weight of the selected alcohol.

When these were ground and mixed, /5 mol.-

7 weight of the organic acid halide was added very slowly under continued trituration. The mass, at first milky, assumed a canary yellow color which gradually changed to a deep orange. This reaction was accompanied by a rise in temperature. This ceased when the orange color appeared, showing that the reaction was completed. The product consists of organic sulphur compounds of undetermined composition.

To illustrate some of the advantages to be gained by the use of the crude reaction product collecting agents as compared to the principal and best known collecting agent, namely x-anthate, the following examples are set forth:

As a general procedure the sample of ore was ground wet in a ball mill with a suitable pI-I modifier. When sufliciently ground, the pulp was transferred to either a Fagergren or a Denver Sub A flotation machine and the flotation reagent and frother were added. The pulp was then subjected to agitation and aeration and the froth concentrate was removed.

The designation R. P. is employed in the following tables to indicate the reaction product.

To illustrate the present invention, charges of copper ore from Utah were prepared and treated, comparison being made between the various chemical flotation reagents contemplated by this invention and potassium ethyl Xanthate as collector:

Tabulation #1-C'opper ore from Utah Copper igi? Tailings recovery Flotation reagent used Lbs/ton er Cent per cent per cent pcopper copper in concentrate K ethyl xanthate 0. 1 12. 2 0. 1 88.8 NaONS ethylalcohol I benzoylchloride R. P. 0. 05 19.12 0.1L 90.0 NaCNS-N. amylalcohol i benzoylchloride R. P 0.1 14. 08 0. 09 92. 2

NaCN S-N, butylalcohol r benzoylchloride R. P" 0. 1 14. 8 OJ 092 91. 3 NaCN S-N. amylalcohol iuroylchlorideR. P 0.15 13.04 0.1 90.3 NaONS N. butyla1coholv iuroylch1oride R. P. 0; 15" 18. 96 0. 13 87. 6 NH4ON-S-N. butylalcohol iuroylchloride R. P} 0. 15 8. 28 0.095 91. 5

en zoylbromide-R. PM... 0.1 10.12 01062 90.0

. LEGEND.-R. P. stands for Reaction Product.

1 Emulsol used as a frother only with this reagent; cresylic acid being used in another tests.

Iron recovery per cent LD. concentrate Copper recovery percent in concentrate Illustrating the greater selectivity of water soluble alkali metal salts of the reaction products over xanthes, a sulphide copper from Utah was prepared for flotation and tested with the 01- 5 lowing results:

Lba/ton Y 246384 I 8 l 6 n m mmmmni t i h m m u n e a 151692 arn 98990 Hm wlm $88889 Gym-i p t pe n ovmm Cm 223221 Mubm 111111 m wmw 00000 fl D 3 TD M 701619 e a5 5 41 a 8 6 111121 a r t P m t 4022.68 .1 m w 255455 0 8 222211 mm 222222 000000 0 0 0 0 0 Q The selectivity with respect to iron is quite pronounced on this ore.

Tailings per cent copper To illustrate the compatibility of the reaction products with xanthates and the greater selectivity obtained by the addition of the reaction products of this invention to xanthates, different percentages of the reaction products were added to xanthate in various stages of its preparation. Also, a water soluble alkali salt of the reaction product was mixed with xanthate in different Tabulation #4.--C'opper ore from Utah Flotation reagfent used I noted that the copper recovery is generally increased when the reaction product is employed instead of potassium ethyl xanthate.

To compare the value of the reaction product collecting agent with xanthates, a sulphide copiron , witlthe Concentrate Per cent Per cent copper l Cresylic acid used as a frother.

LbsL/ton Lbs/ton Ethyl xanthate Tabulation #2.Copper ore from Arizona Flotation reagent used 1 per ore from Arizona was used. The results are shown in the following table R. P. flotation reagents were prepared from alcohol, benzoylchlorlde and NsONS.- Only the alcohol is indicated in tabulation.

1 Fuel oil mix employed as a frother in each case.

The reaction product enables several per cent more copper to be recovered than does either the purified ester or even a larger quantity of either potassium ethyl xanthate or potassium amyl xanthate.

To demonstrate the collecting effectiveness and selectiveness of the reaction products dissolved in cresylic acid or amylalcohol as compared to xanthate, a sulphide copper ore from Arizona Tabulation #3.C'opper ore from Arizona Flotation reagent used 1 was prepared for flotation and treated following results:

R. P. flotation reagents were prepared from an alcohol, benzoylchloride and NaCNS; only the alcohol is R P.'s were used in form of 33.3% R. P. to 66.7% cresylic acid and 1-1 B. P. in pentasol and freed from the alkali halide by filtration.

1 Oresylic acid fuel oil mix used as (rather.

An increased copper recovery and a concenproportions. All of these preparations were used trate containing less iron shows the greater seon a Utah sulphide copper ore as shown in the lectivity of the R, P. flotation agents. subioined tabulation,

indicated in the tabulation.

Tabulation-#5.-Copper ore from. Utah. v

Concentrate T 1 Copper Iron Flotationreagentsnsed- 0.02lb./ton ofore with mgs cresylic acid as a Per Per in 5 t in frothcr cent cent 553 g 3 copper trate trate (a) K. salt isopropyl R.

P., pentasol xanthate, 40%... 20. 6 14.9 0. 10 90. 5 25. 0 (D) K. salt lsopropyl R.

P., 60%; pentasol xanthate, 40.% 18. 6 12.1 0.12. 89. 2 22.9 (c) K. salt isopropyl R.

.. R, 60%; pentasol xanthate, 40%"--. 20. 0 13.2 0. 12 89. 5 22. 2 (d) K.saltisopropylR.

P., 60%; pentasolxanthate, 40% 18. 4 15.5 0. 91. 6 30.1

K. salt isopropyl R.

P., 100 22.4 13. 7 0.12 89.1 21.2 Pentasol xanthate, 100% 16. 8 21. 1 0.12 89. 9 43. 8 K. salt isopropyl R. P.,

80%; ethyl xanthate,

20% 20. 6 13. 9 0.12 89. 3 24- 7 K. salt isopropyl R. P.,

60%; ethyl xanthate,

40% 19.4 16. 6 0.12 89.2 30.7 K. salt isopropyl R. P.,

40%; ethyl xanthate,

60% 18.4 18.8 0.12 89. 4 37. 3 K. salt isopropyl R. P.,

20%; ethyl xanthate,

80 17. 2 21. 4 0. 12 89. 3 43. 7 Ethyl xanthate, 100%". 15.8 19.9 0.11 90. 2 46. 4 K. salt isopropyl R. P.,

LEGEND:

(a) Wet K. salt of isopropyl R. P. mixed with commercial pentasol xanthate dried.

(b) Wet K. salt of isopropyl R. P. mixed with pentasol xanthate ingredients dried.

(c) Isopropyl reaction product mixed with pentasol, CS2 and enough KOH to form double salt and dried.

(d)hDtry K. salt of isopropyl R. I. mixed with commercial pcntasol xant a e.

To show the selective action of the reagents of this invention upon sulphide lead and sulphide zinc minerals over sulphide iron mineral as compared with xanthates, a series of tests were made on a lead-zinc ore from Idaho.

The procedure followed consisted in taking off a lead concentrate by means of a small amount of collecting agent and the usual cresylic acid frother and after conditioning with copper sulphate and additional collecting agent, a zinc concentrate was taken off. This is shown in Tabulation No. 6, less iron and more lead and zinc being recovered with the R. P. agent than with the xanthate or Minerec A, a xanthic acid formate as made under the Fischer Patent 1,684,536.

Tabulation #6.Lead-zinc ore from Idaho Assays. per cent Assays, per cent concentrates tailings 6O Flotation reagent Lbs/ton Pb Zn Fe Pb Zn Fe Pot. salt isopropyl reaction product 0.04 57.6 8.1 4.4

Do 0.15 3.4 42.6 6.4 0.45 046 5.5 Pot. salt 2d butyl reaction product 0.04 55.4 8.1 4.6

o 0.15 2.8 43.6 6.2 0.48 0.36 5.5 Pot. salt pentasol reaction product 0.04 55.3 8.1 4.4 Do 0.15 2.8 42.0 6.4 0.43 0.29 5.4 Ethyl xanthate. 0.04 50.2 9.4 6.3 Do 0.15 1.5 40.5 7.4 0.15 0.13 5.1 Mmerec A. 0.034 52.1 9.6 6.3 Ethyl xanthate. 0.154 1.88 44.0 7.8 0.13 0.16 5.05 MinerecA 0.34 51.6 9.6 6.3 Pot. salt pentasol reaction product 0.154 1.73 45.8 6.8 0.13 0.08 5.3

. in tiate Reva. hates cent tailings Flotation reagent Lbs/ton Pb Zn Fe Pb Zn Fe Pot. salt isopropyl reaction product 0.04 780.4 7.8 4.3 Do 0.15 10.1 85.5 13.2 9.5 6.7 82.5 Pot. salt 2d butyl r action product. 0.04 81.2 8.0 4.7 Do 0.15. 8.2 86.6 12.5 10.6 5.4 82.8 Pot. salt pentasol ie I action product 0.04 82.1 8.1 4.6..

0 0.15 8.7 87.7 13.7 Ethyl xanthate. 0.04 92.1 11.6 8.1

Do 0.1.5 4.786.61615 1\I111ereo A 0.034 91.4 11.0- 7,4 Ethyl Xanthate. 0.154 5.7 86.6 15.8 MinerecA 0.34 92.5 11.8 8.1 Pot. salt pentas action product 0.154 4.8 87.0 13.4

I claim:

1. The improvement in the concentration of ores by flotationwhich comprises subjecting a sulphide ore in the form of a pulp to a flotation operation in the presence of an effective quantity of a froth flotation agent comprising a reaction product of an aliphatic monohydric alcohol, an alkali thiocyanate and a carbocyclic acid halide.

2. The improvement in the concentration of ores by flotation which comprises subjecting a sulphide ore in the form of a pulp to a flotation operation in the presence of an effective quantity of a froth flotation agent comprising a reaction product of an aliphatic monohydric alcohol, an alkali thiocyanate and benzoylchloride.

3. The improvement in the concentration of ores by flotation which comprises subjecting a sulphide ore in the form of a pulp to a flotation operation in the presence of an effective quantity of a froth flotation agent comprising a reaction product of an aliphatic monohydric alcohol, an alkali thiocyanate and furoylchloride.

4. The improvement in the concentration of ores by flotation which comprises subjecting a sulphide ore in the form of a pulp to a flotation operation in the presence of an effective quantity of a froth flotation agent comprising a reaction product of an aliphatic monohydric alcohol, an, alkali thiocyanate and benzoylbromide.

v5. The improvement in the concentration of ores by flotation which comprises subjecting a sulphide ore in the form of a pulp to a flotation operation in the presence of an effective quantity of a froth flotation agent comprising a solution of a reaction product of an aliphatic monohydric alcohol, an alkali .thiocyanate and a carbocyclic acid halide in an organic liquid.

6. The improvement in the concentration of ores by flotation which comprises subjecting a sulphide ore in the form of a pulp to a flotation operation in the presence of an effective quantity of a froth flotation agent comprising a cresylio acid solution of a reaction product of an aliphatic monohydric alcohol, an alkali thiocyanate and a carbocyclic acid halide.

7. The improvement in the concentration of ores by flotation which comprises subjecting a sulphide ore in the form of a pulp to a flotation operation in the presence of an effective quantity of a froth flotation agent comprising an amyl alcohol solution of a reaction product of an aliphatic monohydric alcohol, an alkali thiocyanate and a carbocyclic acid halide.

8. The improvement in the concentration of ores by flotation which comprises subjecting a sulphide ore in the form of a pulp to a flotation operation in the presence of an efiective quantity of a froth flotation agent comprising a water soluble reaction product of an aliphatic monohydric alcohol, an alkali thiocyanate, a carbocyclic acid halide and an alkali hydroxide.

9. The improvement in the concentration of ores by flotation which comprises subjecting a sulphide ore in the form of a pulp to a flotation operation in the presence of an effective quantity sulphide ore in the form of a pulp to a flotation operation in the presence of an effective quantity of a froth flotation agent comprising (1) a reaction product of an aliphatic monohydrlc alcohol, an alkali thiocyanate, and a carbocyclic acid halide and (2) an alkali metal salt of an alkyl sulphur derivative of carbonic acid.

11. The improvement in the concentration of ores by flotation which comprises subjecting a sulphide ore in the form of a pulp to a flotation operation in the presence of an effective quantity of a froth flotation agent comprising (1) a reaction product of an aliphatic monohydric alcohol, an alkali thiocyanate, and a carbocyclic acid halide and (2) an alkyl sulphur derivative of carbonic acid.

CORNELIUS I-L KELLER. 

